Valves check valves

Gate valve Globe valve Check valve Angle valve... 

Swing Check Valves These valves (Fig. 10-156) are used to prevent reversal of flow Normal design is for use only in horizontal lines, where the force of gravity on the disk is at a maximum at the start of closing and at a minimum at the end of closing. Unhke most other valves, check valves are more likely to leak at low pressure than at high pressure, since fluid pressure alone forces the disk to conform to the seat. For this reason elastomers are often mounted on the disk. Swing checkvalves are available with low-cost insert bodies. 

Whenever it is necessary to control the process level, pressure, temperature, etc., a control station is installed. A control station may be as simple as a single control valve or it may contain several control vahes, block valves, bypass valves, check valves, and drain or vent valves. 

The piping around any facility, other than the straight pipe connecting the equipment, is made up primarily of a series of control stations. Flow from one vessel goes through a control station and into a piece of pipe that goe.s to another vessel. In addition to considering the use of block valves, check valves, etc., all control stations should be designed so that the control valve can be removed and any bypass valve is located above or on a level with the main control valve. If the bypass is below the con tiol valve, it provides a dead space for water accumulation and corrosion. 

Wliile all the flame arrester types disenssed above have a solid arresting element (matrix), the hydranlic (liqnid seal) flame arrester contains a liqnid, nsnally water, to provide a flame barrier. It operates by breaking np the gas flow into discrete bnbbles by means of an internal device to qnench the flame. A mechanical nonretnrn valve (check valve) is sometimes incorporated to prevent the displacement of liqnid dnring or after a flame event (deflagration or detonation). 

Sperr-klmke, /. catch, pawl, ratchet, detent, -kreis, m. block circuit, wave trap circuit, -metail, n. ply metal, -rad, n. ratchet wheel, cog wheel, -schichtenzelle, /. solid photovoltaic cell, -ung, /. shutting, etc. (see sperren). -ventil, n. stop valve, check valve, shut-off valve, -waffe, /. defensive weapon, -wasser, n. sealing water. 

Plug Cock Plug Valve Check Valve... 

Figure 5.5. (/) Butterfly valve (g) Non-return valve, check valve, hinged disc type...

STRAIGHT TEES ANGLE TEES. GATE VALVES. . CHECK VALVES... 

This kind of valve is essential when tight shutoff is needed, particularly of gas flow. Multipass plug cocks, butterfly valves, slide valves, check valves, various quick-opening arrangements, etc. have limited and often indispensable applications, but will not be described here. 

The gas processing system for this particular solar hydrogen fuel cell system consists of several gas scrubbers, a gas regulator, water filter, and a few valves, check valve and flashback arrestors. 

Failure data for the relevant failure modes of the block valves, check valves and relief valves exist in data handbooks. The available statistics are assumed to be the mean (equal to the value reported in Table 1, taken from Wu (2007)) and the standard deviation (arbitrarily assumed equal to four times the value of Table 1). 

In the present case, uncertainty about the failure rates of the pumps, block valves, check valves and relief valves is represented using the lognormal probability distributions defined in the probabilistic approach, whereas the possibihly distributions introduced in the possibihstic approach are used to represent the uncertainty about the failure rates for the explosive valves and the tank. 

Shutdown basically follows the reverse procedure stop pump, open recycle, close block valve, check valves with ammonia, check nitrogen seal system (which should remain in operation even when no transfer is being made). 

Chemical Pirn and its Operation Non-return Valves (Check Valves)... 

There are no block valves, check valves, or automatic-control valves on the low-pressure inlet or outlet-piping systems that may isolate the exchanger. 

Cleaned and flushed (instruments, control valves, check valves protected)... 

As a consequence of the incident in the NPP Biblis unit A, the German authority required for all German NPPs (PWRs and BWRs) an exhaustive investigation of the adequacy of the isolation of the low pressure systems connected to the reactor coolant system. The available isolation means (isolation valves, check valves), their actuation, the instrumentation for detection of an overpressure or overtemperature condition in these systems have been investigated in detail. All German NPPs have analysed the Biblis event for applicability to their plants. In specific cases, design improvements or administrative measures have been implemented. 

Check Valves. Check valves are used in gas lines where it is important to assure that gas can only flow in one direction. They are not recommended for use as the primary means of shutoff but as a backup should the primary shutoff valve fail. They are commonly used in systems on the purge gas inlet line to assure that process gas will not back up into the purge gas supply. This is especially important if a common purge gas reservoir supplies many gas delivery systems. In some systems, many different gases may be vented into a common header. If this is the case, separate check valves should be installed on the vent lines for the separate gases to assure they will not be able to mix in the system. Check valves can also be used on the process gas delivery line to prevent any backup of gas from the process into the gas supply system. They can also be placed directly after the cylinder to prevent any backup and contamination of the cylinder. 

Rtlckstreuung, Reflexion backstop Rtlcklaufsperre backstop valve/ check valve (backflow prevention) Ruckschlagventil, Rtickflusssperre, Rtlcklaufsperre, RUckstauventil badge... 

Prior history of isolation equipment (block valve, check valve, etc.) failures. 

Most line has pipe fittings, such as elbows, tees, reducers. It also has block valves, check valves, or instruments, such as control valve and oriflce flow meter. They will cause pressure drop in tine. In this section, we will discuss how to calculate pressure drop thru pipe fltting, block valve, check valve, and control valve using loss coefficient, K, since their pressure drops are required in hydraulic loop pressure profile calculation. Darby s 3-K. method will be used to calculate these pressure drops [ 12]. It is better than two K method or equivalent line length methods. Fittings and valves pressure drop (in terms of pressure head, H) is calculated by flillowing equation, ... 

Filter housings commonly incorporate protective devices, such as shut-off valves, check valves, reverse-flow valves and a bypass facility. Shut-off valves are usually incorporated in the filter head, automatically sealing the outlet and inlet lines when the filter housing is removed (for example, to replace an element). They also have the advantage of minimizing air entrainment during replacement of the filter element. It should be noted that shut-off valves, where fitted, are normally effective only at low system pressures (that is, not full system pressure unless specifically stated). 

Valves list the estimated number of isolation valves + check valves 4.5.4 Heat Rejection Segment... 

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